In .NET Framework 2.0, System.Net has a new feature called Tracing. System.Net Tracing is very useful for some special scenarions:

-Client and server are on the same machine, in case of this network monitor doesn’t work for you as it can’t capture the loop back traffic.

-Secure communication like HTTPS.

Here is a sample about using System.Net tracing to resolve a SSL problem. Consider follow scenario, an AuthenticationException throw out on frontend web service when it calling the backend web service.